GB951065A - Resinous condensation products and laminates prepared therewith - Google Patents

Abstract

A co-condensate is made by heating a substantially anhydrous mixture comprising, by weight, 50-96% of a phenol-formaldehyde resole, 30-2% of a silane or siloxane having one of the formulae: <FORM:0951065/C3/1> and <FORM:0951065/C3/2> wherein R is an alkyl group having 1 to 4 C atoms, R1 is an aryl radical and each R2 is an alkyl or alkoxy radical of 1 to 4 C atoms or an aryl radical, and n is 0, 1 or 2, and 20-2% of glycidyl polyether having an epoxide equivalent of at least 170, the epoxy resin being introduced initially or after reaction of the other materials, and removing the liberated alkanol. The reaction may be effected by heating the reactants to reflux temperature and removing the alkanol formed, but is preferably effected under reduced pressure. When making the co-condensate it is preferred to add a little polycarboxylic acid or anhydride, e.g. mellitic, chlorendic, phthalic, terephthalic and adipic acids or anhydrides, the dianhydride of pyromellitic acid being preferred. The products are preferably diluted to 40-70% (wt.) of resin solids with an anhydrous low-boiling acyclic mono- or poly-hydric alcohol of 1-4 C atoms, e.g. ethanol, n-propanol, isopropanol or ethylene glycol. The resoles and organosilicon reactants used are well known, and the epoxy resins used are those obtained by reacting epichlorohydrin with a phenol or a polyhydric alcohol, e.g. as described in U.S.A. Specification 2,640,037. In a typical example (1), a glycidyl polyether of bisphenol A is added to the reaction product of phenol, paraformaldehyde and hexamethylenetetramine and the mixture is heated under reduced pressure; phenyltrimethoxysilane is then added and the mixture is again heated under reduced pressure with removal of methanol by distillation, cooled and mixed with isopropanol to provide a solution containing 60% (wt.) of resin solids.